Amateurs enable professional astronomy

NGC 253, also called the Sculptor Galaxy has a dwarf galaxy companion first spotted in an amateur astronomer's photo contest entry. This image, though, was made with the National Optical Astronomical Observatory's 4-meter telescope in Chile. Credit: T.A. Rector/University of Alaska Anchorage, T. Abbott and NOAO/Aura/NSF

The new year brought a wave of astronomy news - including ways students, teachers, and amateurs help the professionals study the Universe.  Start reading or jump to learn about:

  • Pro-Am Collaboration: amateur astronomers work with the pros to discover galaxies, observe black holes, and study stellar eclipses.
  • Crowdsourcing: Galaxy Zoo's legacy continues to produce revolutionary science from citizen scientists' work.
  • Using Astronomy in the Classroom: Many projects presented at the American Astronomical Society's Winter Meeting highlighted how astronomy inspires kids to embrace science.

Pro-Am Collaboration

Let’s start with an example of how there’s more to a pretty picture than you might think. Australian astrophotographer Michael Sidonio submitted a picture of the galaxy NGC 253 to the Greenwich Observatory’s annual Astronomy Photographer of the Year competition. He made the final cut and earned a Highly Commended award

San Jose State University astronomer Aaron Romanowsky happened to see Sidonio’s image and noticed a smudge off to the side of the galaxy. Rather than dismiss it as an artistic flaw in Sidonio’s work, Romanowsky dug a little deeper. He found the same smudge in an Italian amateur’s image of NGC 253. 

Armed with that evidence, Romanowski justified using the research-grade Chart32 telescope on the Andean plateaus of Chile. The higher magnification of the 80-centimeter telescope revealed the smudge as a diffuse object. That wasn’t enough to tell what the object was, but did let Romanowksi’s science team unlock the next level in the astronomy research game. The 8-meter Subaru Telescope observes the Universe perched more than four kilometers above sea level on Mauna Kea’s volcanic peak.

The Subaru’s powerful instruments revealed that the smudge captured in Sidonio’s backyard telescope is a dwarf galaxy companion to NGC 253. The peer-reviewed paper to be published in the Minutes of the Royal Astronomical Society Letters (arXiv preprint: 1512.03815) explains that, as the dwarf galaxy orbits NGC 253, its larger companion’s gravitational pull tears the smaller galaxy apart.  

The announcement earned Sidonio a new burst of fame. The former competitor in strongman competitions had placed his face on cereal boxes. Now the Australian press lauded him for helping science. (Check out his interviews with the Canberra Times and The World Today.) The dwarf galaxy discovery could help research into galactic mergers as well as the nature of dark matter.

All because an amateur took a pretty picture.

More formal collaborations rely on the complementary strengths of professional and amateur observations. The professionals use sophisticated instruments attached to large telescopes on mountaintop observatories or in outer space. But they can’t do it very often. Amateurs’ equipment may not be as sophisticated, but they can do whatever they want for as long as they want. That lets amateurs occupy a useful niche in variable star astronomy. They have the freedom to make hundreds of observations over the course of weeks, months, or even years.

An artist's impression of a black hole consuming its binary stellar companion. Credit: Nasa, Esa, Martin Kornmesser (Esa/Hubble)

A Japanese-led research team recently sought amateurs’ help to study a black hole. Amateur astronomy happens in the visible spectrum that ground-based telescopes can detect. Black hole astronomy, on the other hand, usually relies on x-ray and gamma-ray space telescopes. 

Both can see V404 Cygni, a black hole binary system consisting of a black hole orbited by a companion star. As the star’s orbit brings it close, the black hole shreds gas from the star’s surface. The cloud of gas spirals to its doom in the black hole’s deep gravity well. Photons that dodge the black hole’s event horizon escape as x-rays and light up the surrounding spiral of gas like a neon sign. A 200-millimeter telescope - medium-sized in amateur astronomy terms - will capture V404 Cygni’s brightening and dimming as the companion star swings around the black hole.

When V404 Cygni brightened again last June, Kyoto University scientists asked amateurs for help. The scientists could get observations from Nasa’s Swift space telescope, but they could not get the hundreds of visible spectrum observations they needed. The researchers combined amateur observations with data from space telescopes to refine our understanding of how black holes consume matter from companion stars. Their findings were published in the peer-reviewed journal Nature (behind the paywall at doi:10.1038/nature16452).

Eclipsing binary systems are less dramatic than black hole binaries, but the science is just as valuable. Take the case of TYC 2505-672-1. (You can’t have creative names for all 100+ billion stars in the Galaxy.) From the perspective of observers on Earth one of the binary system’s stars eclipses the other every 69 years. The way the combined light from the two stars appear to change during the eclipse reveals insights into the stars’ physical properties. 

Studying the eclipse, however, requires hundreds of observations over the course of four years. The scientists pulled data from the Catalina Real-time Transient Survey’s archives, but its holdings only run through May 2014 - and even then it only held 78 observations of TYC 2505-672-1. Fortunately members of the American Association of Variable Star Observers collected 246 observations of the eclipse’s final years. 

The resulting research (arXiv preprint: 1601.00135) reveals that the primary red giant’s companion star may be a “stripped red giant” - a dying star about the same size as the Sun. Many questions remain about how a system like this came to be. The next eclipse won’t be until 2080-2083, but the amateurs will be ready.

Scientists presented several current and proposed amateur collaborations at the American Astronomical Society’s winter meeting earlier this month:

Crowdsourcing Astronomy

Amateurs don’t need telescopes to work with professional astronomers - a web browser will do. Galaxy Zoo was the original crowdsourced astronomy project. Its volunteers classify the shape of galaxies in images from the most advanced observatories on Earth and in space. Galaxy Zoo’s scientist reported that, eight years into the project, citizen scientists still contribute more than 4.7 million classifications a year. That adds to a rich trove of data for professional research. Hundreds of independent research projects cite Galaxy Zoo as a source. A few announcements last month highlight the lasting impact that citizen scientists make.

The fuzzy green dots in the top row are "green pea" galaxies discovered by the citizen scientists at Galaxy Zoo in images from the Sloan Digital Sky Survey. The same galaxies appear in greyscale images from the Hubble Space Telescope. Credit: Galaxy Zoo / Sloan Digital Sky Survey / Nasa / Esa / STScI

Among Galaxy Zoo’s earliest “accidental” discoveries were the green pea galaxies. People noticed green blobs among pictures of normal galaxies. They collected examples in the project’s forum which attracted the attention of Galaxy Zoo’s scientists. More than 150 research papers cite the resulting research (MNRAS open access doi: 10.1111/j.1365-2966.2009.15383.x).

An international team of scientists used green pea galaxies to explain a key phase in the Universe’s history. Their research, published in Nature (behind the paywall at doi:10.1038/529159a) found that green peas emit ultraviolet light intense enough to ionize intergalactic gas molecules. The findings support a theory that, one billion years after the Big Bang, early galaxies released photons intense enough to re-ionize intergalactic hydrogen. 

The press release and subsequent media coverage rarely mentioned the amateur contributions that made this work possible. Yet how long would green pea galaxies gone undiscovered if a few citizen scientists hadn’t said “Huh. Does anyone know what this is?”

A host of poster presentations at the AAS meeting used data from Galaxy Zoo’s citizen scientists to study galactic evolution:

  • Quenching histories of galaxies and the role of AGN feedback (ADS: 2016AAS...22711904S)
  • The power spectra of non-circular motions in disk galaxies (ADS: 2016AAS...22733402W)
  • Ultraviolet to Infrared SED (Spectral Energy Distribution) Analysis of Nearby Late-Stage Merging Galaxies Using CIGALE (ADS: 2016AAS...22734225W)
  • Bivariate mass-size relation as a function of morphology as determined by Galaxy Zoo 2 crowdsourced visual classifications (ADS: 2016AAS...22734228B)
  • Galaxy Zoo Hubble: First results of the redshift evolution of disk fraction in the red sequence (ADS: 2016AAS...22734240G)
  • Galaxy Zoo Hubble: Crowdsourced Morphologies for 169,944 Galaxies (ADS: 2016AAS...22734241W)
  • Galaxy Zoo CANDELS Data Release I: Morphologies of ~50,000 Galaxies With z ≤ 3 in Deep Hubble Legacy Fields (ADS: 2016AAS...22734242S)

Using Astronomy in the Classroom

Space and dinosaurs catch the imagination of schoolchildren around the world. Research and programs presented last month demonstrate how astronomy can inspire students to embrace science.

The Nasa/Ipac Teacher Archive Research Program, or Nitarp, pairs science educators with professional astronomers in a year-long research project. Educators who get hands-on experience conducting real research carry their insights and excitement back into the classroom to influence a generation of students. They use data from the space agency’s space telescope archives to study stellar evolution, active galactic nuclei, and more. The teachers present the results of their research side-by-side with professional scientists at the AAS Winter Meeting. You can read more about this year’s teacher research in my post “Teacher research advances astronomy". 

The American Astronomical Society itself made news when it adopted the WorldWide Telescope (WWT). The WWT app pulls data from the world’s professional observatories to create astronomical visualizations. Its easy-to-use interface lets teachers bring the Universe into the classroom. At the same time its rich data sets make it useful for astronomical research. Now that Microsoft Research turned the WWT into an open source project, the AAS can give the project a governance and review structure to channel the astronomy community’s contributions.

Other education-focused posters presented at the AAS meeting include:

  • Assessing NASE Professional Development in Astronomy Workshops (ADS: 2016AAS...22721402D)
  • A New Coherent Science Content Storyline Astronomy Course for Pre-Service Teachers at Penn State (ADS: 2016AAS...22724505P)
  • Development of an Online Exoplanet Course for In-Service Teachers (ADS: 2016AAS...22724507B)
  • Skynet Junior Scholars: Bringing Astronomy to Deaf and Hard of Hearing Youth (ADS: 2016AAS...22724609M)
  • Sharing Gravity’s Microscope: Star Formation and Galaxy Evolution for Underserved Arizonans (ADS: 2016AAS...22724611K)

Several research projects conducted by high school and undergraduate students were presented at the AAS conference. Among them:

  • The Role of Exotic Molecules In Model Exoplanet Spectra (ADS: 2016AAS...22713827C)
  • Orbit Refinement of Asteroids and Comets Using a Robotic Telescope Network (ADS: 2016AAS...22714115L)
  • Time Series Photometry of the Variable Stars AN Lyn and UU Lyn (ADS: 2016AAS...22714406L)
  • An Observational Study of Pulsations in Proto-Planetary Nebulae (ADS: 2016AAS...22743704H)
  • Modeling Asteroid Geometries using Photometry at the Glendale Community College North Observatory (ADS: 2016AAS...22744607G)

This is just a snapshot of the range of contributions amateurs make to the science of astronomy. Check out these other stories to see detailed examples of others: